When you squint your eyes you can see better. Why?!
Question: speaking of eyes, mine are telling me allergy season is coming
Answers: speaking of eyes, mine are telling me allergy season is coming
It is all related to a phenomenon called depth of focus. The larger an aperature (optical opening of a lens) the shorter the depth of focus. The smaller an aperature, the larger the depth of focus. The depth of focus of a lens is the distance between the nearest clear position of an object and the furthest clear position of an object. For instance, if you are using a 35mm camera and focus the lens on an object say 2 feet away, the image on the film will APPEAR to be clear for objects nearer or further away than two feet. BUT, the smaller the aperature, the greater the distance between the near and far clear points. Therefore, even though an object is not positioned exactly at the focal point of the lens, if the aperature is small the object will APPEAR to be in focus because the depth of focus has extended out to include the position of the object.
So what does this have to do with your queston? By squinting your eyes you are artificially decreasing your aperature to the optics of the eye. Therefore, things that were more blurry can appear clearer because you are extending the depth of focus of your eyes to better include the position of the object you are viewing. This does not work exactly like a camera, though. In an eye, because the aperature change from squinting is not symmetrical nor perfectly controlled you can actually get some optical interference from squinting. So there is a limit to how much improvement you can get from squinting and in some cases squinting can actually decrease clarity.
it reduces glare.
really?!?
cuz i see worse when i squint my eyes...
my doctor says i gots perfect eyesight
I BELIEVE it's kind of like lenses in photography.
I'm not sure, though.
when you close a lens a bit, it focuses all the light from objects onto one spot on the film. When you squint, you focus the light onto one spot on your retina.
I am really just guessing. My head is dwelling in the realm of photography today.
Ugh, allergies. Yuck.
i have no idea..maybe cus ur focusing more on one spot? idk...lol i have no idea. my eyes are itchy too! although that could be because i have 5 cats living in my bedroom...
Take a lens, any lens. Lets say that a bundle of light is coming from the left, and it hits a lens . All these little parallel lines move towards the lens. The rays that hit the center of the lens move straight through, undeviated. The light rays hitting the lens at a place to the side, hit the lens at an angle and are bent or go in a different direction. When these light rays get to the other side of the lens, they hit the air again and are again bent. All together, the light rays bend either to a point on the right side, called the focal point, at the focal distance, OR, they bend as IF they came from a point on the left side.
Either way, the central light rays are going through a plate glass window, no change in direction.
When we pinhole, all of a sudden we can see clearly as we're using light rays that are not deviated hardly at all. Squinting is a way of pin-hole-ing. That's all there is to it.
We can use this to determine if someone who is seeing a certain level with their glasses, might see better if we adjust their refraction. So some will say the vision with glasses or with Rx is 20/50, PH 20/25. It removes all the refractive problems such as myopia, hyperopia, astigmatism,....